GB/Z 24636.2-2009Geometrical product specifications(GPS) - Statistical tolerance - Part 2: Statistical tolerance values and their indication on drawing (English PDF)

Foreword

GB /Z24636 "Product Geometrical Specifications (GPS) Statistical Tolerance" is divided into the following five parts.

--- Part 1. Terms, definitions and basic concepts;

--- Part 2. statistical tolerance values and their designations;

--- Part 3. Part Lot (process) of the statistical quality indicators;

--- Part 4. statistical tolerance design based on a given level of confidence;

--- Part 5. Assembly batch (hole, shaft with) the statistical quality indicators. This section GB /Z24636 Part 2. This part of Appendix A, Appendix B and Appendix C are informative appendix. This part of the National Product Size and Geometry Technical Standardization Technical Committee proposed and centralized. This section drafted by: Machine Productivity Promotion Center, Shandong University of Technology, Zhongyuan Institute of Technology, Zhengzhou University. The main drafters of this section. Bear Xiong, Zhang Yu, Zhao Zexiang, Zhang Linna. Geometrical product specifications (GPS) statistical tolerances Part 2. statistical tolerance values and their designations

1 Scope

This part of GB/Z 24636 specifies the values of statistical tolerance and the method of indicating them on drawings. This part applies to linear dimensions to which statistical process control is applied, and in particular to fit dimensions of a comparatively high tolerance grade; it also applies to variable quality characteristics that have two-sided specification limits and to which statistical process control is applied.

GB /Z24636 provisions of this part of the statistical tolerance values and labeling in the drawings. This section applies to the linear size of the application of statistical process control, especially with a higher tolerance level with the size; also applies to Bilateral specification limits and the application of statistical process control metrology quality characteristics.

2 Normative references

The following documents contain provisions which, through reference in this part of GB /Z24636, become the provisions of this section. Any reference to the date of the citation All subsequent amendments (not including errata content) or revisions do not apply to this section, however, encouraged to be reached under this section The parties to the agreement examine whether the latest versions of these documents are available. For undated references, the latest version applies to this book section. GB /Z20308 Geometrical product specifications (GPS) master plan (GB /Z20308-2006, ISO /T R14638..1995, MOD)

3 Statistical tolerance value form

The statistical tolerance of process quality indicators is determined by the application of specific statistical tolerances. Both upper and middle are dimensionless normalized numbers Value, the lower is the value of the dimension.

3.1 Process Quality Indicators statistical tolerance value The statistical tolerance values (P * d, P * c, P *ql) of the process quality indicators are expressed as a percentage and selected by the recommended form. Generally take a decimal point Bit or two. Of these, Pd, which requires exceptionally high, can be expressed in parts per million (10-6).

3.2 Standardized two-dimensional statistical tolerance value The two-dimensional statistical tolerance values are expressed as dimensionless numbers in (C * p, ) and (C * p, delta *) arrays whose sizes are defined by the upper direct mass index Standard or indirect quality indicators.

3.3 Dimensional two-dimensional statistical tolerance values The statistical tolerance values based on the two-dimensional statistical parameter interface with the actual dimensions are expressed by the values in the array (sigma, Delta) whose size is given by Standardized two-dimensional statistical tolerance value conversion.

3.4 General requirements of the quality level and the value of the statistical tolerance Statistical tolerances General requirements of the quality level can be 3sigma and 4sigma quality level of recommendation, according to industry and product characteristics to choose one of them As the default statistical tolerance common requirements, the implied values of the statistical tolerance shown in Table 1. Table 1 statistical tolerances General requirements implicit statistical tolerance tables Quality level C * p delta * * Pd * Pc (M ± T/6) P * c (M ± T/4) P * 3sigma 1 0 0 0.27% 68.3% 86.6% 11.11% 1.00 1.00 4sigma 1.33 0.5 0.125 0.0244% 76.3% 92.6% 7.84% 1.16

1.19 The specific SIGMA quality levels and statistical tolerance values are given in Appendix A.

4 Statistical tolerances in the design of the label

The general requirements and specific requirements for statistical tolerances may be expressed in terms of symbols and values, respectively, in the relevant drawings and technical documents.